Maneuvering machine



T. P. DAVENPORT Re. 23,592

ATTORNEY DCC- 9, 1952 T. P. DAVENPORT Re 23,592

MANEUVERING MACHINE l Original Filed Nov. 18, 1949 l 3 Sheets-Sheet 2 FIG. 4.

IN VEN TOR. THERON F? DAVENPORT A T TRNE Y Dec. 9, 1952 T. P. DAVENPORT MANEUVERING MACHINE 3 Sheets-Sheet I5 Original Filed Nov. 18, 1949 m .mi

INVENTOR. THERON P AVENPRT BY j f I /Mr/4 Reissued Dec. 9, 1952 UNITED STATES PATENT OFFICEl MANEUVERING MACHINE Theron P. Davenport, Port Neches, Tex.

Original No. 2,548,202, dated April 10, 1951, Serial No. 128,202, November 18, 1949. Application for reissue October 29, 1951, Serial No. 253,745

Matter enclosed in heavy brackets 1 appears in the original patent but forms no part lof this reissue specification; matter printed in italics indicates the additions made by reissue.

4 Claims.

The invention concerns a computing and plotting device which may be used in connection with commercial radar installations on board merchant vessels for the purpose of computing the courses and speeds of one or more known or unknown obstacles which may be observed by radar while navigating in dense fog or other low visibility, thus enabling the shipmaster on the observing vessel to navigate his ship in such a manner as to avoid collision.

The invention is more particularly adapted for commercial purposes and iinds its greatest use in permitting the shipmaster to quickly and accurately determine the course and speed, point of passing ahead and point of closest approach of all known or unknown obstacles within the normal operating range of commercial radar at sea.

An advantageous feature of the invention is that the device may be operated in conjunction with any existing commercial or military radar installation without altering its design. Being manually operated, except for the electrically driven chart, it is not dependent on electrical or mechanical connections with the radar set. The recording of the information obtained from the radar scope is plotted by the operator in the same manner in which distance and direction measurements are plotted on a stationary plotting sheet or navigational chart, and is not in any way dependent on wave impulses. The number of problems which may be solved simultaneously is limited only by the skill of the operator. Any shiprnaster or deck oiilcer may operate the device eiTectively without prior instruction.

The cost of producing the device is relatively small and well within the means of even the smallest ship operating company.

The need for such a device has been amply demonstrated by the numerous collisions and near collisions occurring between radar equipped vessels while operating in fog or other low visibility. It is believed that this device will prove more satisfactory than methods heretofore used in determining the course, speed and closest approach of other vessels inasmuch as the actual movement of the vessel over the earth is proiected upon a moving chart geared to the speed of the ship, thus giving a true picture of the relation of movement between the vessels involved in the problem. An important feature is the reliable running check which may be maintained on the course and speed of approaching, crossing, overtaken or overtaking vessels. A few simple movements of the new type parallel rule Within the 2 1 bearing circle, in plotting the information received from the radar scope, will immediately indicate any deviation in the course or speed of the observed vessel.

The machine is small and compact, and may be constructed either for mounting on a pedestal or hinged to a bulkhead of the pilot house readily available to the master or watch olcer.

By slightly altering the design the machine may be made to carry a strip chart of harbor' channels showing buoys, lightships, lighthouses, ranges and other objects close to the channel oi" immediate concern to the navigator while navigating by radar in dense fog. The speed of the chart is synchronized with the speed of the ship over the earth. Departure is taken from a known position, such as a lightship or buoy, and the in dications of the chart are made to correspond with this position. If the speed has been accurately determined the ship should arrive at various known positions at the saine instant as indicated on the chart. This is of great value when interpreting the information given byradar, as the indications of the scope should correspond with that of the moving chart, thereby greatly reducing the chances of an error in piloting in confined waters.

The endless charts may be removed from the machine at any time, and offer positive evidence of all radar information plotted.

The machine is rugged in construction and has few moving parts.

effectively without prior instruction.

The machine is capable of producing extremely rapid and accurate solutions to problems oi maneuvering from information presented by the radar scope. No special technical training is required. Any watch oicer capable of operating and obtaining ranges and bearings from the radar may apply this information to the maneuvering machine and obtain an accurate solution to probf lems relating to the course and speed of approach? ing or crossing vessels when navigating in dense fog on the busy trafllc lanes of the seas.

The speed control rheostat, which synchronizes the speed of the chart with that of the ship, is the only adjustment required to place the machine in operation. The presentation of the chart and the basic design of the bearing circle and parallel rule are similar to that to which the ocean navigator has long been accustomed.

The invention will be readily understood by referring to the following description and the acr companying drawing, in which:

Anyone familiar with radar' .and plotting bearings may operate the machine Fig. 1 is a top view of a maneuvering machine embodying the invention.

Fig. 2 is a sectional view in elevation taken on the line 2-2 of Fig. 1.

Fig. 3 is a sectional view in elevation taken on the line 3-3 of Fig. 2.

Fig. 4 is a top view of the machine with the bearing circle and parallel rule removed.

Fig. 5 shows a section of the chart used in solving the problem described hereinafter as EX- ample 1.

Fig. 6 shows a section of the chart used in solving the problem described hereinafter as Een ample 2.

Referring to the drawing, a casing I is provided, the casing I having a cover 2. The casing I,.1maybe mounted-on :eithera pedestal or a bulkhead, the numeral .3 indicating the upper portion of a pedestal. A chassis comprising a pair of side members 4 and a connecting shelf -like member 5 is disposed within Vthe casing I and is secured therein -by a pair iof clamping members 3. The clamping members `Ii are secured to the lower portions of the side members 4 and are adapted to receive thumb `screws 'I which extend thru the bottom -of the casing I.

An endless, -paper covered, sheet brass chart 3 is mounted yon rollers 9, I0, II and I2 and vis adapted to be moved at a speed synchronized with that of the ship. The-chart il is driven by a-.small fractional vhorsepower variablespeed electrcf'motor I3 through a series of reduction gears I4,.a drive shaft I5, a pair of belts I6 and the roller IU, which is a driven roller. The speed of thechart 8 is controlled by a manually operated rheostat (not shown), which is calibrated in knots.

The motor I3 andthe yreduction gears I4 are supported `upon the shelf-like member 5, Vwhile the drive shaft I5 is supported at its ends in bearings formed in the side members 4. The driven .roller I0, which is located at the top and forward endvof the machine, is fitted with teeth I'l around its extreme ends which engage correspondingslots in ythechart 8. The driven roller I0 is connected to thedr-ive shaft I5 by the belts I6, sheaves I8 and I9 being provided for the belts I6 at the ends of the driven roller I!) and the drive shaft I 5, respectively. Thus any movement of rthemotor I 3 is transmitted to the chart 8.

The driven roller I ll .and rollers 3 and I2, which are idler rollers, are carried in bearings ZIJ, 2I and .Z2-on arms 23, 24 and 2,5 extended in a iixed posi tion from 4side members 4. Roller II, which is also an idler roller, is carried in bearings `2t which are mounted Yat the .ends of levers 21. The levers `2.1 are pivotally secured .to the side members Il, andthe .ends thereof .opposite the bearings are acted upon Aby springslZB whichV bear against the clamping members E. This arrangement maintainstension .onthe chart 8, and also permits the .chart 8 to be removed and replaced.

A .bearing and guide plate 29, over which the chart .8 moves, is secured between the side members 4 adjacent the upper edges thereof. The plate 29 provides a solid working surface beneath the chart 8 when bearings are being plotted.

An annular plate 30 is mounted on `anges 3l, the .flanges 3I being secured ito the outer surfaces .of the side members 4, adjacent the upper edges thereof. v'Ifl'ie plate 30 is centered .directly over the bearing and guide plate 29. The plate 30 carries a bearing circle Y32 von its outer width. The bearing circle 32 is graduated in degrees (0 1:0360), land may be set and clamped to read either true or relative bearings,

4 A mounting ring 33, which may be rotated within the bearing circle 32, and which carries the new type parallel rule hereinafter described, is supported upon the inner width of the plate 3Q. The parallel rule, which has been designed to meet the special requirements of this machine, may be swung in azimuth through 360 degrees. It includes a xed arm 34, which is disposed across the 'center of the bearing circle 32 and is securely fastened at its ends in sockets provided on the mounting ring 33. The fixed arm 34 advantageously is made of transparent plastic, as

is `a movable arm 35, and is graduated at intervals representing knots or yards. The fixed arm 34 is used to plot the bearing and distance of the target. The movable arm 35, or course and speed rarm, Vis .secured at itsendsto arjpair of racks 36, which arentted in bearings 31 ,on `the mounting ring 33 and operated, in or out as the case may be, by a pair of pinion gears 3B. The gears 3B are secured to the ends cfa shaft39 which is rotatably mounted on themounting ring 33 ,and is provided with knobs for turning it. The movable arm v35 is graduated at intervals representing knots or yards, andis used .in deter-V miningthe course and speed of the .target vessel.

The working area of the .chart 8 enclosed .by the bearing circle 32 vand the mounting ring V33 represents either miles or `yards as required .by circumstances of the problem involved, rand covers the extreme range of ycommercialradarin normal operation at sea. As shown in Fig. .1, Ythe chart 8 is graduated .at intervals representing knots along a line 40 drawn through the center of the chart 8. Line 40 .represents ythe ships track. Parallel lines 4I, 42 and 43 are drawn at intervals, representing .knots .or yards, .on each side of the center line 40. Lines 4I, 42 and 43 facilitate plotting, vallowing the operator to determine ata glance the appreximate .distance cf the .target ship.

Charts 8 may be replaced by removing theplate 30, carrying the bearing circle 32 and the parallel rule, and lifting the chassis from the casing I. Upon releasing the .tension on the roller II vthe chart 8 may be removed and .replaced from the side.

To illustrate the simplicity of operation two problems are presented:

Example 1 Assume that the observing vessel is navigating in dense fog, with'radar operating perfectly and the ship on ,course 360 degrees true, speed `15 knots and maneuvering machine synchronized to this speed. At 2300 a'target isobserved on the scope bearing Ll5 vdegrees true, `distance 14 miles. The parallel rule is'rotated andlined up with -45 degrees on the bearing circle 32, vand the distance measured cn the xed arm 34 of the rule. A small dot, together with any note of time, vis located at this point. At 2312 the target bears 35 degrees true, distance 12 miles. A second dot is located upon the chart at this pointandthe parallel rule swung in azimuth until the outer, movable arm 35 is made to intersect and line up with the first and second dots. Since the target 4is moving from right to leitthe course -is read in the left Semi-Circle of the bearing circle s2 at the' point of intersection vwith the pointer attached to 'each end of the fixed arm 34 of the rule. ln this case the course is found to be 316 degrees true. The true speed of the target is read -on the-outer ,arm 35, thesdistance between the two dots .being 4.2. miles. Since the ytime between the rst and second bearingwas `12 minutes, or 1/5 hour, the speed of the target is 21 knots. By projecting the line joining the position dots across the center line 40 the point of closest appreach, together with the time and distance when the target is dead ahead on the ships track, may be ascertained. By plotting subsequent positions along the t'argets projected track any deviation from the course or speed will be immediately in evidence.

To carry the problem further, at 2324 target bore 22 degrees, distance 10.8 miles. At 2336 target bore 006 degrees, distance miles (closest approach). At 2340 target crossed dead ahead at 10 miles distance. At 2348 target bore 3494 degrees, distance 10.2 miles, and at 2400 target bore '334 degrees, distancer11.1 miles. Danger-of collision with this vessel is past and the data may be erased from the chart 8, which is then ready for the next problem, or if desired, the chart B may be retained as a record.

Example 2 Assume that the observing vessel is proceeding in dense fog on course 180 degrees true, speed 15 knots, with radar in normal operation and maneuvering machine set to the ships course and speed. At 0200 a target is observed on the scope bearing 170 degrees true at 15 miles distance. This position is plotted on the maneuvering machine as described in Example 1, and the target kept under continuous observation. At 0208 the target bears 175 degrees true, 12 miles distance. This second position is plotted on the machine and the targets course and speed determined. In this case the target ship is found to be on true course 298 degrees and advancing along its track at the rate of 1.8 miles in eight minutes, giving it an hourly speed of 13.5 knots. The target ships course line is projected across the chart 8 as described in Example 1, and its position plotted at intervals of 8 minutes, or 1.8 miles, along this track. Radar bearings are taken at 8 minute intervals (note below) and checked with the predicted positions along the track, thus indicating that the target ship is holding its original course and speed.

At 0216 target bore 183 degrees true, distance 9 miles.

At 0224 target bore 200 degrees true, distance 6.6 miles.

1At 0232 target bore 230 degrees true, distance 5 miles.

, At 0240 target bore 265 degrees true, distance 5.5 miles.

At 0248 target bore 290 degrees true, distance 7.5 miles.

The word target as used herein is not to be confused with targets referred to in military science. During the war an object detected by radar was assumed until proven otherwise to be a foe, and hence a potential target. For this reason the Word "target is now used generally to denote any object capable of being observed by radar. To the navigator it means something to miss rather than something to hit.

The invention may be modified in various ways without departing from the spirit and scope thereof.

I claim:

1. A computing and plotting device comprising a supporting frame, a plurality of rollers mounted on the frame, one of the rollers being a driven roller, a continuous chart mounted on 1 Closest approach.

the rollers and adapted to be moved longitudinally upon rotation of the driven roller, means for rotating the driven roller at predetermined speeds, a planular member mounted on the frame and disposed immediately adjacent the under side of the chart, an annular p-late'mounted on the frame and disposed immediately adjacent the upper side of the chart, a bearing circle carried by the annular plate, a mounting ring rotatably mounted With respect to the annular plate and disposed concentrically with respect to the bearing circle, and a parallel rule mounted on the mounting ring, the parallel rule including a iixed arm which is disposed across the centerof the bearing circle and is secured at its ends to the mounting ring, a pair of racks slidably mounted on the mounting ring and disposed transversely with respect to the fixed arm, a movable arm secured at its ends to the racks and disposed in parallel relation with the fixed arm, a pair of pinion gears rotatably mounted on the mounting ring and acting upon the racks to move them longitudinally, and means for manipulating the pinion gears manually.

2. A computing and plotting device comprising a flat member, a chart having a portion thereo] extending along the flat member, a motor coupled to the chart for moving it along the flat member at predetermined and substantially constant speeds, a bearing circle located adjacent the chart on the side opposite the fiat member, and a parallel rule having a first arm with an edge disposed diametrically across and rotatable about the center of the bearing circle, the parallel rule also having a second arm which is offset an adjustable distance from the center of the bearing circle.

3. A computing and plotting device comprising a supporting frame, a plurality of rollers mounted on the frame, one of the rollers being a driven roller, a chart located on the rollers and adapted to be moved longitudinally upon rotation of the driven roller, a motor coupled to the driven roller for rotating it at a plurality of constant speeds, a fiat member rigidly mounted on the frame and disposed immediately adjacent the under side of the chart and being substantially coetensive with the width of the chart, an annular ring mounted on the frame and disposed immediately adjacent the upper side of the chart, a bearing circle carried by the annular ring, a mounting ring rotatably mounted with respect to the annular ring and located inside the annular ring so that it is disposed concentrically with respect to the bearing circle, and a rule attached to the mounting ring and movable different distances from the center of the bearing circle for plotting and measuring distances and bearings on the chart.

4. A computing and plotting device comprising a frame, an annular member secured to the frame and having a bearing circle thereon, a fiat member rigidly secured to the frame and located substantially parallel to the annular member and adjacent the side of the annular member which is opposite the bearing circle, the flat member being substantially coetensive with the width of the chart, a chart located between the annular member and the flat member and having a graduated center line agired toy its upper surface before it passes under the bearing circle, the center line being maintained substantially along a diameter of the bearing circle, a motor coupled to the chart for moving it along said diameter of the bearing circle at predetermined and sub- 7 stantially constant speeds, a mounting ring rotatably A'mounted with respect to the `annular member and located inside the annular member so that yit is disposed concentrically with respect to the bearing circle, `and a scale attached to the mounting ring and movable different distances from the center of the bearing circle for plotting and measuring distances and bearings on the chart.

THERON P. DAVENPORT.

Y REFERENCES CITED The followingA references are of record in the file of this paient or the original patent:

u UNrrED STATES kPATENTS v-ifurrloer Name Date 10,133 Hinkley 1 Oct. 18, 1853 Number 46,348 413,250 586,975 r 939,999 964,773 1,098,621 1,896,997 2,437,243 lo 2,438,522

Number Name :Date Gilette Feb. 14, 1865 Farciot Oct. 22, 1889 ONeal July 27, 18,97 Fraser et al Nov. 1.6, 19,09 Guillo July '19, 1910 Gst June 2, 1914 Bennett Feb. 7,1933 Curtis Mar. 9, 1943 Smith Mar. 30, 1948 FOREIGN PATENTS Country Date Great Britain Feb. ,21, 1907 Great Britain Oct. 1, 1913 Switzerland Apr. 1, 1920 Germany Mar. 27, .1934 France 1. Sept. 3, 1934 

